On Thu, Apr 22, 2010 at 04:32:20PM -0600, Bjorn Helgaas wrote: > > > - event = kmalloc(sizeof(struct acpi_bus_event), GFP_ATOMIC); > > > + event = kmalloc(sizeof(struct acpi_bus_event), GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE); > > Just in terms of reading the code, this solution is fairly ugly. > I think __GFP_NOTRACK should be sort of the last resort, after we've > ruled out all the more conventional strategies. > > Has anybody tried any of the alternatives Vegard suggested here: > https://bugzilla.kernel.org/show_bug.cgi?id=14998#c35 ? > First of all I really want to thank Vegard for taking the time to look at this. There are three options in the bugzilla entry: > 1. Copy the struct "by hand" and use strncpy() for the strings to avoid > the uninitialized areas. The downside is that copying by hand is a maintainance hassle. > 2. Allocate the event with kmalloc() instead of on the stack and free it > after the call to acpi_bus_receive_event(). The problem with this is that if a future function uses stack data instead of allocated data we're back at square one. Perhaps if we put a huge warning sign it would be OK. There isn't a sparse anotation for this, but it would be nice to have. One other place where we could use it would be passing stack space as a DMA transfer buffer. > 3. Allocate the event with kmalloc() and pass ownership of the structure > to acpi_bus_receive_event() to avoid the copying altogether. I don't think the kmalloc() is meant here because it says we avoid the copying. This is a simple api change but in the end I didn't think it was as nice as the current api. I did write a patch to do it though so if anyone prefers that I can send it. In the end, I decided it was easiest to just to change the kmalloc() to a kzalloc(). regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
